Monday, 29 December 2008

Ficus conundrum

What is the real identity of this Ficus?

There are a number of very similar giant Ficus grown in Spain and Portugal. Sorting them out is quite complicated. Most of the trees in Lisbon are Ficus macrophylla. But this tree at Monserrate is something else!

It is not just at Monserrate that these strangler figs have botanists in a fix. The Ficus magnolioides of Borzi has been a source of considerable confusion. This was finally sorted out relatively recently: S. Fici, F.M. Raimondo, ON THE REAL IDENTITY OF FICUS MAGNOLIOIDES in Curtis's Botanical Magazine vol: 13 nº2, p.105 ,1996.

The correct name of Ficus magnolioides Borzì var. magnolioides (Moraceae) is F. macrophylla Desf. ex Pers. subsp. columnaris (C. Moore) P.S. Green. This name is derived from C. Moore's Ficus columnaris C. Moore & F. Muell., an endemic Fig of the Lord Howe Island which Fici et al identified as a subspecies of Ficus macrophylla of the Australian Mainland (Moreton Bay Fig). The subspecies is distinguished by its abundant aerial roots. Ficus macrophylla has little or no development of aerial roots.

The "Banyan" fig growing on the Chapel is currently labelled as Ficus macrophylla. Significantly the name in Spanish is given as "Ficus de Hojas de Magnolia" - a throw-back to the days when this fig was known in Southern Europe as Ficus magnolioides. However, Walter Oates in his description of the Chapel in 1929 describes a large spreading Ficus rubiginosa in its place.

From this description the leaves and fruits fit the Monserrate tree. However there is no mention of the most striking characteristic : the aerial roots! This is most probably since the authors are describing Ficus rubiginosa from dry climates - like the Canary Islands. In its Australian habitat this species produces abundant aerial roots, trees growing in the relatively humid climate of Madeira are also prolific in this aspect.

Other candidates: "On Lord Howe Island, a rare fig, Ficus columnaris, sends roots down from the branches which reach the ground and become new trunks, and so the tree walks in all directions until it becomes a small forest. Several of the more tropical banyans also walk in this way, including Australia's Ficus virens [leaves like a poplar], India's Ficus retusa [leaves like Ficus benjamina] and Ficus benghalensis [distintive and characteristic leaves] and the aptly named Ficus polypoda [Sorry Russell but this must be F. platypoda - no indumentum to leaf backs]. A famous ancient Ficus benghalensis near Poona in India has hundreds of trunks and a circumference of a kilometre". (Russell Fransham)

None of the above.

So what about Ficus rubiginosa? does it have aerial roots?Edward F. Gilman and Dennis G. Watson of the University of Florida state in their paper on this species that "it does not develop the profusion of roots that some other [ficus] do."